srinathdevelopment:
Dewalt:
I have connect 2 op-amp togeter (LM324N) and I don´t get the right result. What do u recommend? what ap-amp shuld I use and how to connect it?post your circuit diagram.
off hand, i'd say even 1 op-amp is more than adequate... you need to however do some work to design the bias and gain within swing range... say bias your signal to 1.7V as the midpoint.... and put a gain of 60 odd... and feed 3.5v to the analog ref in arduino to get max range.
working with 2 opamps has its benefits but needs far more careful design work
Without knowing the details of the strain guage its premature to guess how to bias the bridge... We also need to know the accuracy requirement before designing in detail. The CMRR figure might be important for instance. The LM324N may prove inadequate for the accuracy desired too, it has a CMRR of 65dB worst case, offset of 5mV, and tempco of offset of 30uV/C